Lead poisoning is a serious health problem affecting millions of Americans, particularly children. The EPA and HUD consider lead paint to be a primary source of the poisoning. Lead is no longer a constituent in commercially sold paint and government agencies have called for its removal in older homes. A central problem to find lead-paint surfaces is the lack of rapid, inexpensive, reliable methods for measuring levels of lead in concentrations as low as l mg per cm2. We propose a new type of x- ray fluorescent detector that should result in a highly efficient, sensitive detector whose quantitative measurements of lead concentration are independent of the paint substratus or the detector energy resolution. The device will make use of newly available, inexpensive inorganic scintillator phosphors viewed by recently developed small photomultiplier tubes or by PIN silicon diodes. Our aim in Phase I is to prove the principals of the method. In Phase II, we will build and test a prototype of the lead paint detector.